Up to the present time, when it was desired to connect the ends of two structures, of which one is flexible, for example the end of a tarpaulin for covering a lorry on the edge of the side panel that the transporting platform comprises, the end of a mobile blind, of a glasshouse cover, the lower edges of big tops or emergency shelters, of wall fabrics, of two parts of a garment . . . , various types of joining elements have been proposed.
For example, in the case of fixing a flexible cover to a rigid structure, the following means are conventionally employed:
systems employing eyelets, hooks and elastic members which present the drawbacks of not ensuring great tightness and especially of having a mediocre resistance in the case of lateral loads, being given that the tension is not distributed uniformly along the fixation; furthermore, such systems are not practical to unfold and cannot be rendered automatic;
fixations employing a section in the form of a gutter on which is engaged a flexible bead connected to the end of the flexible structure to be fixed. Such a type of fixation, employed in particular in the domain of camping, for example in the case of caravan canopies, dismantling of big tops, presents the advantage of having a good tensile strength and a good tightness, but, when the flexible element (or cover) is of great length, maneuvering is delicate in view of the very considerable frictions. Moreover, the end opposite the flexible element (cover) must be dismantled simultaneously, which precludes certain applications, such as for example the covering of a lorry;
the fixation of the "curtain rail" type (rail connected to the cover) which, although it is practical to use and may be rendered automatic, presents the drawback of not allowing the part opposite the cover to be left in place, this eliminating certain applications, and, furthermore, as the tension is not uniformly distributed along the cover, concentrations of stresses are produced at the level of fastening of the roller. Moreover, this type of fixation cannot be used when the cover must be totally removed (the latter can be rejected only at the end of the rail).
If it is desired to connect together two flexible structures, the most wide-spread device is the so-called "slide fastener" of which the two elements are borne along each of the edges of the grooved structures. Such slide fasteners which comprise metal teeth fitting in one another under the action of a slide element, are complex and expensive to manufacture. Furthermore, their aesthetic appearance is a debatable point and when one of the teeth is twisted, such an assembly is no longer reliable. To overcome this drawback, it has been proposed to produce slide fasteners operating by fitting of two flexible sections in each other. This type of closure is used in particular for hermetically closing plastic packings. However, this solution presents the major drawback of offering only a mediocre tensile strength, which renders it inappropriate for numerous uses.
A simple device, which is economical to manufacture and easy to employ, has now been found, and this forms the subject matter of the present invention, which overcomes all these drawbacks.